I'm no expert and didn't even take the time to Google it, but I'd guess that fat free (which doesn't ACTUALLY mean zero fat, by the way) half and half involves corn syrup or some other kind of sugar. The sugar-free Smarties? Probably a chemical sweetener of some sort.

Which reminds me, one time my mom spilled some of that fat free dairy free artificial coffee creamer on her counter, and when it dried it peeled off in one piece and looked like plastic.

Eat real food!